Rule of thumb for me even living in the city is to avoid driving if I can at all costs. BART and Caltrain are great because they let off not very far from the park (BART is a little bit of a walk, but you'll be able to follow the hoards of people walking the same direction; If you do absolutely have to drive, I suggest one of the two parking lots on 2nd between Folsom and Harrison. It was $10 to park in the one I parked in and the other was $15, which beats $30+ for the lot or parking on the street. You can park at meters close to the park, but all the ones in proximity run the entire length of the game and don't stop at 6pm like most do in the city (It's a horrible and expensive way for the city to cash in, as always), but if you don't mind a walk, you might get lucky and find street parking from Mission to Harrison between 3rd and 2nd streets where the meters run like normal and stop at 6pm. Good luck!!